In an Optical Burst Transport Network (OBTN), a client service is encapsulated into an Optical Burst Unit (OBU) at a source node first, and then sent through an optical channel; after receiving the OBU, a destination node decapsulates the OBU to obtain the client service. In consideration of requirements in various aspects, such as rate adaptation, scheduling granularity and compatibility and so on, a common practice is to add a layer of Transmission Adapter Units (TAUs) between a client service layer and an OBU layer, and the client service is mapped to a transmission frame first, and then encapsulated and adapted into an OBU through a TAU.
Since the length of the transmission frame is determined by the service, a plurality of transmission frames may be encapsulated in one OBU, or one transmission frame is encapsulated in a plurality of OBUs. Therefore, how to completely and accurately obtain the transmission frame from one or more OBUs through parsing remains to be a technical problem to be solved.